Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

Radio made by OP-AMP

Radio made by OP-AMP

This is normal superheterodyne radio receiver. It does not use any coils. It uses a filter and oscillator made by OP-AMP. Converter is also constructed by a OP-AMP detector.
When the plus input is positive , it pass through the antenna signal. When the plus input is negative , it does not pass through the antenna signal. Therefore antenna signal is converted to 40kHz IF signal. IF filter is constructed by the low pass filter. Q of it is higher than 1. So it works as a band pass filter. See fig 4! IF-AMP is a normal non-inverted-AMP. Detector is OP-AMP detector. You can use a normal diode detector indicated in fig 3. But I wanted to use OP-AMP also in this block. Low pass filter selects only audio signal. The output impedance of OP-AMP is about 1k ohm. Therefore it can not drive a speaker directly. So I use a transformer. But now I think it is better to use a emitter follower indicated on another page. I can hear JOAK(594kHz) and JOAB(693kHz) by tuning the oscillator. This radio has the total gain 4+23+29+4+17=77dB. 1m wire is enough antenna.

Visit Here for more.







 

More Articles to Read

An Arduino-controlled automated whiskey distillery
An Arduino-controlled automated whiskey distillery
The Rex800 looks like a dinosaur Terminator
The Rex800 looks like a dinosaur Terminator
Home Environment Monitor
Home Environment Monitor
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
App note: Noise analysis for high-speed op amps
App note: Noise analysis for high-speed op amps
Skill Sunday: Arrays
Skill Sunday: Arrays
App note: Infrared remote control implementation with MSP430FR4xx
App note: Infrared remote control implementation with MSP430FR4xx
Gesture Controlled Smart Home
Gesture Controlled Smart Home
Design for a Wideband, Differential Transimpedance DAC Output
Design for a Wideband, Differential Transimpedance DAC Output
Wrist thrusters let you fly through the water effortlessly
Wrist thrusters let you fly through the water effortlessly
Bertan/Spellman 225-20R HV power supply teardown
Bertan/Spellman 225-20R HV power supply teardown
Blinking Christmas Lights
Blinking Christmas Lights
Adjusting clock with alarm, hygrometer & thermometer on 1.8″ ST7735 display
Adjusting clock with alarm, hygrometer & thermometer on 1.8″ ST7735 display
Adding an “extra sense” with rangefinders
Adding an “extra sense” with rangefinders
This wireless game controller looks like a rug
This wireless game controller looks like a rug
How to run your ESP8266 for years on a battery
How to run your ESP8266 for years on a battery
Calibration of a 3-Phase Energy Meter Board on the ADE7754
Calibration of a 3-Phase Energy Meter Board on the ADE7754
Making beats on a tiny Arduino DJ controller
Making beats on a tiny Arduino DJ controller
Qinsi-QS5100 Sn63Pb37 solder profile
Qinsi-QS5100 Sn63Pb37 solder profile

Top


Shares